Space telegraphy.



No. 884,106. PATBNTED APR], 1908. J. s. STONE.

SPACE TELEGRAPHY.

- APPLIOATION FILED MAY 7, 1906.

6 SHEETS-SHEET 1.

No. 884,106. PATENTED APR. '7, 1908.

v J. S. STONE.

.SPAOE TELEGRAPHY. APPLIOATION FILED MAY 7, 190 6.

6 SHEETS-BHEET 2.

PATENTED APR. 7, 1908. J. S. STONE. SPACE TBLEGRAPHY. APPLICATION FILED MAY 7, 1906.

6 SHEETS-SHEET a.

G m/3a PATENTED APR. 7, 1908';

J. s. STONE. 'SPAOE TELEGRAPHY.

APPLICATION FILED MAY 7, 1906.

6 SHEETS-SHEET 4.

Ff -IEL FI' -ll- IWEN D WITH E5 614) PATENT-ED APR. 7, 1908. J. s. STONE. SPACE TELEGRAPHY.

APPLIOATION FILED MAY 7, 1906.

e SHEETS-SHEET 5.

Fl m 2.

ITNESEE 5: HAVEN'T-CIR:

PATBNTED APR. 7, 1908.

J. S. STONE.

SPACE TBLEGRAPHY.

APPLICATION FILED MAY 7, 1906.

e SHBETSSHEET a.

FT -IE- WITH E5 '55 E mm STATES PATENT OFFICE.

'JQHN STONE STONE, F CAMBRIDGE, MASSACHUSETTS, ASSIGNOE TO WILLIAM W. SWAN,

TRUSTEE, OF BROOKLINE, MASSACHUSETTS.

SPACE TELEGRAPHY.

phy, ofawhich t e following is a specification.

g invention relates to the art of transmitting intelligence from one station to another by means of electromagnetic waves without the use of wires to guide the waves to their destination; and it relates more particularly to systems for receiving signals transmitted by such waves.

.The object of the present invention is to increase the selectivity of the circuits which are associated with the elevated conductor system of a space telegra h receiving system. The selectivity of an e ectrical circuit depends upon the rate of change of the impedance 0 such-circuit with respect to variations in the frequency of the forces acting upon said circuit. In order to make such rate of change of impedance as great as pos- 125 sible, I may include 1n the circuit in question a parallel branch circuit containing capacity in one branch and'inductance in the other branch and adapted to balance by its reactance for a persistent train. of electrical oscillations of definite frequency, the reactance of the rest of the circuit. In such case the rate of change with respect to frequency of the reactance of said parallel branch circuit, as

measured between its points of connection with the circuit in which it is included, is

greater-than the rate of change with respect to frequency of thereactance of a serially connected coil or acondenser of like inductance and capacity, respectively; or, in other 40 words, the curve SlIOWIII the variation with respect to frequency of the reactance of said parallel branch circuit is a steeper curve than the curve showing the reactance-frequency [variation of such serially connected coilor condenser. The aforesaid circuit designed so that for a )ersistent train of electrical oscillations of definite frequency the reactance of its serially connected parallel branch circuit shall balance the reactance of the rest of A .50 the circuit, preferably is interposed between the elevated receiving conductor and the res- ,onantreceiving circuit and, by virtue of the proportionment of the electromagnetic con- Specification of Letters Patent.

Application filed May '7, 1906. Serial No. 316,520.

Patented April 7, 1908.

stants of such interposed circuit, the latter may be made extremely unresponsive to oscillations of all frequencies except to very persistent trains of electrical osclllations of the frequency to which the associated-resonant receiving circuit is attuned. .In other words, said interposed circuit may, for -a given frequency, be made much stiffer than if it were made highly res onsive to persistent trains of electrical oscillations of said frequency by means of a serially connected coil and condenser only.

The invention may best be understoodby having 'reference to the drawings which-accompany and form a part of this specification, and which illustrate conventionally several organizations of circuits and apparatus whereby the hereinbefore stated objects may conveniently be realized in practice.

In the drawings, Figure 1 represents 'a space telegraph receiving system which contains a circuit including a parallel branch circuit, having capacity in one branch and inductance in the other branch and adapted to balance by 'its reactance for a persistent train of electrical oscillations of definite frequency, the reactance of the rest of the circuit in which it is included, and which is interposed between an elevated receiving conductor system and a resonant receiving circuit, the resonant receiving circuit being associated with the inductance branch of the aforesaid parallel branch circuit. Fig. 2 represents a modification inwhich the resonant receiving circuit is associated with the condenser branch of the arallel branch circuit. .Fi 3 represents a urther modification in whic the reactance of the parallel branch circuit for a persistent train of electrical oscillations the energy of which is to be received has a negative reactance, the reactance of the rest of the interposed circuit in such case being a positive reactance. Fig. 4 shows a'further modification in which a series of circuits, herein shown as two circuits, is interposed between the elevated receiving conductor system and the resonant receiving circuit, each of said interposed circuits including a parallel branch circuit so proportioned as to balance by its reactance for a persistent train of electrical oscillations of definite frequency, the reactance of the rest of the circuit in which it is included. Fig. 5 shows another modification in .which one of the interposed circuits of Fig. 4 is replaced by a. resonant weeding-out circuit, which is at-.

tuned to the frequency of the waves the energy of which is to be received. 'Fig'. 6 shows st' another modification in which the cir- .cuit interposed between-the elevated receiving conductor system and the resonant weeding-out' circuit includes two serially con-j nected parallel branch circuits each containng ea aclty in one branch and mductance'in :theot er branch and-adapted to present for a persistent train of electrical osclllations of reactances.

' rent amplitude and the abscissae represent the frequency of the waves the energy of which is to be'rece'ived, equal and opposite Fig. 7 shows a further modification'in which the oscillation responsive device is associated with one of. the aforesaid circuits in which the reactance of th'e parallel branch circuit containing capacity in one branch and inductance in the other branch (persistent train of electrical oscilla-i is, fora tions of efinite frequency, equal and opposite to the reactance of the rest of the circuit which includes the parallel branch circuit: Figs. 8 to '15 inclusive are diagrams hereinafter more fully referred to in explaining the theory of operation and the prop'ortionment of the electromagnetic constants of the sys temsillustrated in Figs. 1 to- 7 inclusive. Figs. 8, 10, 12 and 14 are curves drawn to- .rectangular coordinates in which the ordinates represent reactance and the abscissae represents periodicity. Figs. 9, 11, 13 and; 15 are curves drawn to rectangular coordinate's, in which the ordinates representcurperiodiclty.

In the figures, V is an elevated receiving conductor per se; V I E and V I 0 E are elevated receiving conductor systems. M re resents a transformer.

L-an I,,;, respectively, represent the primary and the secondary windings of a transformen C represents a condenser. L represents an inductance COll.

Rrepresents an oscillation responsive de- V106. 1 The variouselements above enumerated are distinguished from each other. as to po sition and function by theuse ofexponentsandsubscri ts." I A is emp oyed' to designate a circuit which includes a parallel branch circuit B and in which athe: resistance for a persistently applied force of definite frequencyis equal and;

-0pposite in sign to that of said parallel branch circuit; 7 p

D designatesi-a resonant receiving circuit and D re resents a resonant weeding-out circuit, eac of said circuits being attuned to theifrequ'encyf of the waves the energy of which is'to be received.

. Referring now toIFigs. s to 3 inclusive,

.impulsive electrical forces.

1, is the frequency natural to the parallel branch circuit or loop circuit B when isolated,

and the curve (2) shows the mode of variation for. progressively increasing-frequencies of the reactance on the driving point of said circuit '13; n,'is the the circuit A when isolated, and the curve (1) represents the mode of variation of the reaetanc e ofsaid circuit A for progressively increasing frequencies. n is the frequency natural to thecircuit A as affected by its the. system A B is extremely responsive when circuit AisI acted upon by persistenttrains. of electrical oscillations.

The resonant receiving circuits D and the resonantweeding-out circuit D of Fig. 5, if employed, are attuned to the aforesaid frequency n, which frequency therefore repre- -.sents the frequency of the waves the energy ofwhich is 'to be received.

As shown in Fi s. 8, and 10, for ersistent trains of electrica oscillations of equency *n. the ordinates of. the curves (1) and (2) are equal and: opposite in sign, so that therefore when; persistent trains of electrical oscillationsiof frequencyn act upon the circuit A the 'reactance. of the circuit B, which is included inicircuitA, balances the reactance of circu'itAr Asshown in Fig 12, for per-' sistent '1 trains of electrical oscillations of' 1 frequency. nftheor'd'inates of the curves (2) and (3) 'areequal. and opposite in sign, so that therefore '1 when ersistent trains of electrical oscillations of equency' 12. act upon the circuit A, thelreactance of the circuit 8, 'wh'ich is included in the circuit A balances the reactance of circuit A,. The curves frequency natural to i shown in Figs. 9, and 11 re resent the variation. withip ersistently app led forces of progressively. increasing frequency .of the cur rent amplitudes developed in the system A B. The. curve shown in Fig. 13 represents the variation with persistently applied forces of progressively increasing frequency of the current amplitudes developed in the system A 'B. Inasmuch as the rate of change with frequency of the reactances of circuits A for frequenciesin the immediate proximity to frequency n is very large, that is to say, as the curves (1) and (2) or, in-Fig. 12-, the curves (2) and (3), are quite steep near the oint on the axis of abscissae marked 11., it

ollows that the rate of current-frequency and'B of Figs. 1 and 2 or A B of Fig.. 3

max'smum ordinate at the point n.

variation in the system- AB of Figs. 1 and 2. or A, B of Fig. 3 will be large,in other words that the curves in Figs; 9, l1 and 13 showing, such current-frequency variation will be quite steep for frequencies in the immediate proximity to frequency n. The curve-showing the variation withrespect to frequency of the reactance of the parallel branch circuit B being a steeper curve than the curve showing the reactance-frequenoy variation of a coil,se e curve (3) in Fig. 12,

employed for making the circuit A extremely,

unresponsive to oscillations of all frequencies exec t to ver persistent trains of electrical oscil ations o the frequency to which the associated resonant receiving circuit is attuned, and inthis' manner the stiffness of the interposed circuit A, i. e., the ratio of its inductance by its capacity, may be made larger.

As shown in Figs. 8 and 10, there is a second frequency at which the reactance of the system A B is zero, and for a persistently applied force of such frequency n, other things being equal, the current amplitude in the systemAB will beequal to that develo ed in said system by persistent trains of osci lations of frequency 'n; but the slope of the currentfrequency variation curve for frequencies in the neighborhood of frequency is much smaller than the slopeof said curve for frequencies in the neighborhood of frequency n, and the area 'inclosed by the curve which has its maximum at the point n on the axis of abscissae. is much greater than that inclosed by the curve which has viously the resonant receiving circuit might be attuned to the frequency a, and in some cases it might be desirable so to attune it,

but inasmuch as the object of thepresent invention is to increase the selectivity of the circuits or circuits which are associated with the elevated conductor system,'l pr'efer'to attune the resonant receiving circuityto that frequency for which the, rate of changeiofz: impedance of the system A B with respect to frequency is the greatest;

When the reactance of circuit B- as fracasured between the points of its connection with the circuit A is positive; or is the reactance of an equivalent coil, for persistently applied forces of frequency n, as shownin Fig. 8,. the amplitude of the current flowing through the inductance branch of circuit B is.

greater than that flowingthroug h the com denser branch thereof. to associate the resonant receir'fin'g circuit D with the inductance branch of the'parallel branch circuit B, as shown in Figs. '1, 4, 5 and Accordingly-I prefer 6. When thereactan'ce of thebranehjcir cuit B is anegative reactance, oris the reactance of an equivalent condenser, for persistently applied forces of fre uency n, as shown in Fig. 10, the amplitu e of the current flowing through the condenser branch of circuit B is greater'than that flowing through the inductance branch thereof. Accordingly in such-case I prefer to associate the resonant receiving circuit B with, the con denser branch of the parallel branch circuit B, as shown in Figs. 2 and 3; but for the purpose -of controlling the degree of coupling, it is often convenient to associate the resonant circuit either directly with the coil of circuit A, or with the coil of circuit B, even when the reactance of the loop circuit is negative.

It will be noted that whenthe fre uency n is lower than that natural to circuit the reactance of circuitB is an inductance react ance and the reactance of the circuit A is a capacity reactance; also that when the frequency n is higher than that natural to the circuit B, the reactance of the circuit B is the capacityrea'ctance while that of circuit A is an inductance r'eactance, as shown in Figs. 8 and 10, respectively. j

In all cases the'coupling between circuit A or A and the elevated conductor system is a loose coupling; in Figs. 1, 2,3; 4 and 6 the coupling between the resonant receiving circuit and the circuit A, or A or A interposed between it, directly or indirectly, and the elevated conductor system is a loose couplin ling is effected have been set forth at length in my prior Letters Patent for example No.

The. means whereby such loose coup-- 767,984, Au 16, 1904, and therefore need 10 respectively, the construction as wellias the mode of operation of the systems shown -in.Figs. 3., 4, 5,6 arid 7 will readily be understood. r

In Fig. 3 it will be noted that the circuit A, contains no elastic element, and that therefore the variation of its reactance with respect to frequency will be linear asshown by curve (3) in Fig." 12. In such case the fre uency for which the capacity reactance of t 1e circuit B is equal to the inductancereactance of circuit A is higher than that natural to circuit B as shown in Fig. 12, and accordingly the resonant receiving circuit had' A. i and the resonant receiving circuit D.

The circuit D is a resonant weeding-out circuit, the function of which has been'explained by me in my prior Letters Patent, for exam le No. 714,756, Dec. 2, 1902.

n Fig. 4 the coupling between the circuits A and A preferably is a loose magnetic coupling and that between circuits A and D may, as shown, be a loose magnetic coupling.

In Fig. 5 the coupling'between circuit A and circuit D preferably is a loose magnetic coupling and that between circuits D and D may be a loose magnetic coupling or it may be the equivalent of a loose magnetic couplin namely, a tight magnetic coupling with cons L and L, in each of said resonant circuits,

having sufficient'inductance to eliminate the effect on the period of circuit .D of its tight.

coupling with circuit D, as heretofore more fully explained by me in Letters Patent No. 714,756, Dec. 2, 1902.

As shown in the system illustrated in Fig. 6, two parallel branch circuits may be included serially in the circuit A, and said circuit may be so designed as to present for r a persistent train of electrical oscillations of rent amplitude for persistently applied" definite frequency equal and opposite reactances, or one of said circuits may be so designed as to present for a ersistent train of electrical oscillations of de nite frequency a reactance e ual and opposite in sign to the reactance of t e rest of the circuit including the parallel branch circuits ,B" and B. The general principle of o eration of the system shownin Fig. 6 may e explained by having reference to Figs. 14 and 15 which illustrate, respectively, the variation of the several reactances and the variation of our forces of progressively-increasing frequency, when the circuits B and B are, adapted to present for a persistent train of electrical oscillations of frequency n equal and opposite reactances.

, Referring particularly to Fig. 14, the

curve (2) represents the frequency-react- I that. the selectivity o frequency n of the waves the energy of which v is to be received. For persistently applied forces of frequency-n the ordinates of curves (4) and (5) are equal and opposite in sign,

and inasmuch as the ordinate of curve (2) for said frequency is zero, it follows that the reactance of the system A B B is zero for said frequency. For two other'fre uencies, namely, n an-d'n the reactance of t e inter: posed circuit in 6 is zero; but it will be noted that the rate of change of impedance with respect to variations in the frequency of the forces acting upon said circuit is much larger for frequencies'in the neighborhood of frequency n than for frequencies in the neighborhood of fre uencies n and n, so

i the circuit in question is higher for frequency 17. than for any other frequency. Accordingly I prefer to attune the resonant receivingcircuit Dto frequency 12, although it will be understood that said either to frequency nor to frequency 11.. I It will be noted that whereas the two fr'eqencies n, and n, are shown as quite different in value, nevertheless the two circuits B" and B preferably are so designed that the two frequencies 11., 'and n, do not differ greatly in value, in which case the ordinates of the curves (4) and (5) for the frequency n of the waves to be received will be much larger than in the caseillustrated in Fig. 14..

It will -my' invention broadly speaking consists in increasing the selectivity of a circuit by balancing the reactance of the circuit fora persistent train of electrical oscillations of definite frequency by the reactance of aparallel bran'ch circuit includin inductance in one branch and capacity in t e other branch, it is not necessary to associate the oscillationresponsive device with a, resonant receiving circuit, but that such device may be. included in the aforesaid circuit, as shown at R in Fig. 7.

- The functions of the parallel branch circuit lettered G have been fully set forth by me in Letters Patent No. 767,994, Aug.- 16, 1904, and therefore need not be further explained herein.

I am aware that it has long been known that a parallel branch circuit containing capacity in one branch and inductance in the other branch would present an inductance reactance for forces of certain frequencies and a capacity reactance for forces of certain other frequencies; but so far as I am resonlant repeiving circuit could'be attuned v be understood that inasmuch as I aware I am the first to employ such a circuit for the purpose, of increasing the selectivity of a wireless telegraphreceiving circuit in the manner hereinbefore set .forth.

It will be obvious that many. modifications may be made in the circuit arrangements an elevated receiving conductor system; a resonant receiving circuit attuned to the fre quency of the Waves the energy of Which-is to be received; and a circuit, lnterposed between said elevated receivmg conductor system and said resonant receiving circuit and including a parallel branch circuit; containing capacity in one branch andinductance in the ot er branch and adapted to balance by its reactance for a ersistent train of electrical oscillations of t e aforesaid frequency, the reactance of the rest of such interposed cir-' cuit.

' 2. In as ace telegraph receiving system, an elevate receiving conductor system; a resonant receiving circuit attuned to the fre-, quency of the waves the energy of which is to be received; and a circuit, interposed between said elevated receiving conductor system and said resonant receivin circuit and including acondenser and a para lel branch circuit, containing capacity in one branch and induct- "ance in the other branch and adapted to present for a persistent train of electrical oscillations of the frequency to which said resonant receiving circuit is attuned, an inductance reactance equal to the capacity reactance of the rest of such interposed circuit.

3. In a s ace telegraph recelving system, an elevated receiving conductor system; .a resonant receiving circuit attuned to the frequency of the Waves the ener y of which is to be received; and a series of circuits, interposed between said elevated receiving conductor system and said resonant receiving circuit and each including a parallel branch circuit, containing capaclty in one branch and inductance in the other branch and adapted to balance, each by its reactance for a persistent train of electrical oscillations of an elevate the aforesaid frequency, the reactance of the rest of such interposed circuit in which it is included,

4. In a space telegraph receiving system,

receiving conductor system; a circuit associated therewith and including a parallel branch circuit, containing capacity -1n onebranch and inductance in the other branch and adapted to balance by its reactance'for a persistent train of electrical oscillations of definitefrequency, the reactance an elevate of the rest of such associated circuit; and-a resonant receiving circuit, attuned tosaid frequency and associated with the inductance branch of said parallel branch circuit.

5. In a space telegraph receiving system, an elevated receiving conductor system; a circuit associated therewith and including a parallel branch circuit, containing capacity 6. In a space telegraph receiving system, I

an elevate receiving conductor system; a circuit associated therewith and including a parallel branch circuit,-containing capacity 1n one branch and inductance in the other branch and adapted to balance by its reactance for a ersistent train of electrical oscillations of d bfinite frequency, the reactance of the rest of such associated circuit; and a resonant recelvmg olrcult, attuned to said frequency and associated with one of the branches of said parallel branch circuit.

7. In a s ace telegraph receiving system,

receiving conductor system; a receiving circuit constructed to o pose zero. reactance to a persistent train 0 electrical oscillations having the frequency of the waves the energy of which is to be received; and a circuit, mterposed'between said elevated receiving conductor system and said receiving circuit and including a parallel branch circuit, containing capacity in one branch and. inductance in the other branch and adapted to balance by its reactance for a persistent train of electrical oscillations of the aforesaid frequency, the reactance of the rest of such interposedcircuit. 8. In a space telegraph receiving system, a closed circuit comprising in its construction a parallel branch circuit, containing capacity in one branch and inductance in the other branch and adapted tobalance, by its reactance for a persistent train of electrical oscillations of predetermined frequency, the reactance of the rest of said closed circuit;

9. In a space telegraph receiving system, a closed circuit comprising in its construction a parallel branchcircuit, containing capacity branch circuit being so proportione as to present for a persistent train of electrical oscillations of predetermined frequency an inductance reactance equal to the capacity reactance of the rest of said closed circuit.

'10." In a space telegraph receiving system,

an elevated receiving conductor system; and In testimony whereof, I have hereunto I a circuit associated therewith and including subscribed my name this 2nd day of May 10 a parallel branch circuit containing capacity 1906.

in one branch and inductance in the other branch and adapted to balance by its react- JOHN STONE STONE ance for a persistent train of electrical oscil- Witnesses:

lations of definitefrequenc the reactance GEO. K. WOODWORTH,

of the rest of said associate circuit. E. B. TOMLINSON. 

